Liver focal lesions and hepatocellular carcinoma in cirrhotic patients: from screening to diagnosis

This short review aims at pointing out the role of ultrasonography (US) as a valuable means for an early detection of liver focal lesions in cirrhotic patients. Among these lesions which may be benign and malignant, hepatocellular carcinoma (HCC) finds its place with an incidence in cirrhotic patients becoming higher as the time passes from the onset of cirrhosis. US is of fundamental importance in the regular screening of subjects with viral cirrhosis because of its sensitivity in evaluating focal lesions (79-82%); however, it is not yet the most valuable method for the diagnosis of HCC for which other diagnostic techniques are needed such as CT (Computerized Tomography), MR (Magnetic Resonance) and the US-guided fine-needle biopsy. In fact, the echo-structure of HCC varies with its dimensions and may mimic that of one of many other liver focal lesions. Lately, some new sonographic techniques have become available that can allow a more accurate investigation of HCC. Among them, the "Tissue Harmonic" and the "Pulse Inversion Imaging" techniques provide a better definition of the grey-scale image thus improving the conspicuity of focal lesions. Color and Power Doppler techniques, while allowing an accurate observation of the lesion vascularization, integrate the sonographic appearance of HCC. The enhancement of the US color Doppler signal obtainable by using echographic contrast agents, represents a further progress for a detailed observation of the focal lesions' micro-vascularization and, thus, for the HCC identification. Further advancements in terms of improvement of the image quality and characterization of the focal lesion are to be expected from the use of "Tissue Harmonic" and "Pulse Inversion Imaging" techniques associated with echographic contrast agents. However, the diagnosis of HCC still rests on the incontrovertible histological evidence obtained by echo-guided fine-needle biopsy.